Polyfluorosulfonamido amines are useful starting materials for various products including: fluorinated surfactants, including cationic, non-ionic, anionic, and amphoteric surfactants; and fluorinated repellents, including (poly-(meth)acrylamides, ureas, imides. Specific applications for polyfluorosulfonamido amines include: electronics applications, nanotechnology, pharmaceutical and pesticide intermediates, catalysts, and firefighting foaming agents.
Rudimentary polyfluorosulfonamido amines can be generally described by the following formula:Rff—S(O)2—NH—(CH2)p—NH2  (Formula A)wherein
Rff is chosen from a C4 to C12 polyfluoroalkyl; and p is an integer from 2 to 8.
Current methods for making polyfluorosulfonamido amines like those of Formula A provide low yields and produce an undesirable fluorine containing by-product representing an economic loss. For example U.S. Pat. No. 4,486,391 contemplates making polyfluorosulfonamido amines of Formula A by reacting a polyfluoroalkylsulfonic acid or an ester thereof with a diamine as represented by the following:Rff—S(O)2—Cl+H2N—(CH2)p—NH2→Rff—(CH2)p—S(O)2—HN—(CH2)p—NH2  (Reaction A)wherein
Rff, and p are defined as above. Unfortunately, in addition to the desired monoamine product, Reaction A also produces an undesirable bis-sulfonamide by-product:Rff—S(O)2—HN—(CH2)p—NH—S(O)2—Rff 
The bis-sulfonamide by-product is particularly undesirable because it shares very similar physical properties with the desired monoamine product thus making isolation of the desired monoamine product difficult and costly. Furthermore, instead of the efficient incorporation of fluorine to make the desired monoamine product, the bis-sulfonamide by-product constitutes a substantial loss of costly fluorinated starting material. The bis-sulfonamide by-product also constitutes an undesirable impurity that can worsen surfactancy, repellency, or other performance characteristics of the desired monoamine product.
Because of the aforementioned disadvantages, it would therefore be desirable to discover a method for making a polyfluorosulfonamido amine wherein the production of a bis-sulfonamide by-product is avoided.